Gneiss
Gneiss
Category
Browse mineral like byproduct specimens identified by the Rock Identifier community.
Gneiss
Gneiss
Aquamarine on Feldspar Matrix
Beryl (Be3Al2Si6O18) with Potassium Feldspar (KAlSi3O8)
Dalmatian Jasper / Dalmatian Stone
Peralkaline Rock (Silicon Dioxide with Amphibole inclusions)
Smoky Quartz (Rough Specimen)
Silicon Dioxide (SiO2)
Howlite
Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)
Ferruginous Quartz
Silicon Dioxide with Iron Oxide inclusions (SiO2 + Fe2O3/FeO(OH))
Moss Agate / Carnelian Agate
Silicon Dioxide (SiO2) with iron and manganese inclusions
Amygdaloidal Basalt
Amygdaloidal Basalt
Quartz / Milky Quartz
Quartz (Silicon Dioxide - SiO2)
Botryoidal Goethite
Goethite (α-Fe3+O(OH))
Rutilated Quartz
Quartz (SiO2) with Rutile inclusions (TiO2)
Petrified Wood
Silicified Wood (SiO2)
Epidote in Quartz
Epidote (Ca2(Al,Fe)3(SiO4)3(OH)) in Milky Quartz (SiO2)
Diorite
Diorite (Intermediate intrusive igneous rock)
Orange Calcite
Calcium Carbonate (CaCO3)
Chrysocolla in Matrix
Hydrated copper phyllosilicate (Cu,Al)2H2Si2O5(OH)4' nH2O on Quartz/Feldspar matrix
Diamond (Colorless/White)
Carbon (C)
Druzy Quartz on Host Rock
Silicon Dioxide (SiO2)
Garnet (likely Almandine or a blend)
Garnet group: X3Y2(SiO4)3, where X can be Ca, Mg, Fe2+, Mn2+ and Y can be Al, Fe3+, Cr3+. Given the dark, somewhat reddish-brown appearance in the image, it's likely Almandine (Fe3Al2(SiO4)3) or a mix with other iron-rich garnets.
Botryoidal Chalcedony
Chalcedony (SiO2)
Granite Gneiss
Gneiss (derived from granitic protolith)
Sandstone (Banded)
Clastic Sedimentary Rock: Arenite
Jasper
Silicon dioxide (SiO2) with impurities
Mica Schist
Mica Schist (Schistose metamorphic rock rich in Muscovite/Biotite)
Rough Garnet (likely Almandine or Pyrope)
Garnet group; Almandine Fe3Al2(SiO4)3 or Pyrope Mg3Al2(SiO4)3
Sandstone (likely with Quartz Veining)
Arenite (primarily SiO2)
Sandstone
Arenite (SiO2 predominantly)
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Orthoclase Feldspar
Orthoclase (KAlSi3O8)
Hematite
Hematite (Iron(III) oxide, Fe2O3)
Sunstone
Oligoclase (a plagioclase feldspar variant), (Na,Ca)(Al,Si)4O8
Granite
Phaneritic Felsic Igneous Rock
Fluorite (translucent octahedral crystal)
Calcium fluoride (CaF2)
Amygdaloidal Rhyolite
Amygdaloidal felsic extrusive rock
Petrified Wood
Silicified Wood (SiO2)
River Pebble Gravel
Hydrothermally modified Clastic Sediment (mainly Quartzite and Chert)
Bornite (Peacock Ore)
Bornite (Cu5FeS4)
Hypersthene
Hypersthene ((Mg,Fe)SiO₃)
Sandstone
Arenite (Sedimentary rock comprising sand-sized grains)
Chert (with Quartz Vein)
Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)
Quartz Pebble (Iron-Stained)
Silicon Dioxide (SiO2)
Hag Stone
Perforated Sedimentary Rock